Several methods are known for limiting these pathologies.
The two treatments most frequently used are self-catheterization and the use of endo-urinary prostheses.
Self-catheterization by the patient with a catheter of large diameter, regularly, is often painful, poorly tolerated, exposed to urinary infections; moreover certain patients cannot or do not wish to self-catheterize. Sounding by a nurse or a physician is limiting and expensive, thus this is rarely carried out over a long term.
The other process used is the placement of an endo-urinary prosthesis which keeps open the inner diameter of the urinary canal to be treated, over a duration which can be long or even permanent.
To this end, endo-urethral prostheses have been used, intended to be placed in the urethra, and endo-ureteral, intended to be placed in the ureter.
A first type of endo-urinary prosthesis known is a cylinder made of mesh, generally metallic, interlaced or in the form of a screen.
Such a cylinder is introduced into the urethra to apply a pressure on its wall. In one well-known configuration such a cylinder is introduced into the urethra with a small diameter, then is expanded radially (which causes shortening of the cylinder). In the expanded state of the cylinder, its mesh is putting pressure on the ureteral mucosa.
Once in place, these prostheses gradually incrust in the wall of the urethra which, with time, covers the prostheses.
This inlay of prostheses in the wall of the urethra makes it very difficult to remove them when that is desired. Moreover, these prostheses can be sources of complications such as a fibrous or polypoid reaction within the prosthesis or at its ends.
The second type of endo-urinary prosthesis is a cylinder made of a metal wire rolled into a continuous joined coil.
Such a prosthesis is generally considered to be temporary and it is typically intended to remain in place in the urethra for duration lasting up to a few months.
The wire has a shape memory such that the diameter of the cylinder is reduced when cold, and greater when hot. It is thus possible to dilate the diameter of the prosthesis, but only to a limited degree.
Thus, it is possible to heat locally the parts of such a cylinder after its placement in the urethra (typically at both ends), to dilate those parts with the aim of avoiding migration of the prosthesis.
However in certain urethras, particularly large and flexible urethras, the prosthesis doesn't have enough push on the wall and it is possible that it will migrate, most often toward the urinary bladder.
Moreover, the configuration with jointed coils of such a prosthesis has a considerable surface area, suitable for attachment of solidified urine. The result is that such prostheses are likely to frequently be obstructed by calcifications, and it is therefore necessary to change them regularly when the intended purpose is a long-range effect.
A known endo-urinary prosthetic, called “double J” is a flexible tube curved at both ends, so as to ensure its being held. One end is housed in the kidney and the other in the urinary bladder.
However, such a prosthesis extends the entire length of the ureter and can thus provoke a feeling of discomfort in the patient. Alternatively, a metal prosthesis with or without thermal dilation can be considered, but is indicated only in precise and limited case (fibrosis, benign or malignant, inside or on the outside of the ureter, and a counter-indication for surgery).
The invention intends to provide a solution overcoming one or more of the disadvantages mentioned above.